A mechanised parking system for automobiles must be reliable, of low cost and the speed of parking or retrieval of vehicles must not be unduly slow.
Various types of mechanised automobile parking apparatus are known, which can be divided into three principle types. The first type acts to convey vehicles between a pick-up station and a plurality of storage stations, on a carriage which in use is thrust under one end of the vehicle and which, by means of appropriate gripping elements, urged or rotated under two of the wheels (either front or rear wheels), conveys the vehicle simply by pushing or pulling it, or by raising and pushing or pulling on these wheels. In either case the vehicle still rolls on at least two of its own wheels. Generally, there is also provided a centering device which acts on the two wheels of the vehicle which are not directly engaged by the gripping elements of the carriage. This centering device serve to position the vehicle in alignment with the axis of the carriage and, sometimes, is completely separate from the carriage. The advantage of centering the wheels of the vehicle with respect to the carriage is that of being able to park the vehicle in a narrow space without risk of damage to the vehicle.
However, because these known systems rely on the rolling of two or four of the wheels of the vehicle itself during its movement problems can be encountered if the user has inadvertently left the handbrake on, or if the gears are left engaged. Moreover, problems are also encountered in gripping the wheels if these are partially or totally deflated. Mechanised automobile parking systems of this type thus exhibit a low reliability in operation even though the mechanised parts of such systems are, in themselves, entirely reliable. In addition to this, the mechanical complexity of the mechanisms for engaging and raising the motor vehicle generally involves high production and maintenance costs.
Another known system provides for the utilisation of pallets on which the motor vehicles are carried, to be deposited in appropriate stalls or compartments. Such pallets therefore have the great advantage of completely raising the vehicle off its wheels and therefore do not rely on the vehicle's own wheels for rolling. When the user arrives to park he must drive his own vehicle directly over the pallet which, by means of a pallet carrier carriage, suitably positioned by an elevator or transelevator, is mounted longitudinally or transversely and introduced directly.
This involves the adoption of a device for exchanging pallets in such a way that whenever a pallet with a motor vehicle is taken off, arrangements are made for its replacement by depositing an empty pallet on the pallet carrier carriage. The lack of a centering device in such systems makes the utilisation of larger surfaces necessary, whilst the necessity of replacing the pallet supporting the automobile when this has been conveyed to the storage station with an empty one for the next vehicle implies the utilisation of greater height. Moreover, the necessity of having a pallet for each storage station involves a considerable increase in production costs.
Another known mechanised automobile parking system provides for the utilisation of movable frames with metal elements having the form and disposition of the teeth of a comb, or else carriages carrying movable comb-like frames. Such systems require the utilisation of frames which are fixed with respect to the movable frames, and the presence of combs anchored in the storage stations, through which the teeth of the movable combs pass with a vertical movement to deposit or retrieve the vehicle, for which purpose it is necessary to provide for the fixed teeth to be approached by the frame having movable teeth, after this has arrived in a position such as to be able to be lowered, thus releasing the vehicle (or to be raised thus retrieving the vehicle) and, this consequently, must be achieved with a movement parallel to the axis of the teeth or with a movement orthogonal to the axis of the teeth themselves.
Such systems convey the automobile either in a longitudinal direction, along the axis of movement of the automobile, or in a transverse direction, that is to say perpendicular to the axis of movement of the automobile. Like the pallet systems, comb systems have the favourable characteristic of raising all four wheels of the vehicle from the ground. The problems which such systems present are essentially due to the lack of mechanical centering of the vehicle, so that other things being equal, it is necessary to provide a greater surface area at the storage station than in the case of systems of the first mentioned type. Also the carriages have a considerable height due to the fact that the lifting mechanism is mounted onto the carriage.
Other known mechanised parking systems, instead of storing the vehicles at fixed locations, keep them in circulating movement. Such systems do not have actual storage stations for the automobiles, but each pallet or frame on which the user has left an automobile is used for recovery of the vehicle itself and is continuously moved, together with all the other vehicles, to bring the various empty pallets or support frames successively to the vehicle deposit or retrieval positions.
This type of apparatus has the serious defect of being extremely slow, and because it provides the contemporaneous movement of all the vehicles, involves a considerable expenditure of energy.